ext/libelf/gelf_dyn.c

/*-
 * Copyright (c) 2006 Joseph Koshy
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <assert.h>
#include <limits.h>

#include "gelf.h"
#include "_libelf.h"

GElf_Dyn *
gelf_getdyn(Elf_Data *d, int ndx, GElf_Dyn *dst)
{
        int ec;
        Elf *e;
        Elf_Scn *scn;
        Elf32_Dyn *dyn32;
        Elf64_Dyn *dyn64;
        size_t msz;
        uint32_t sh_type;

        if (d == NULL || ndx < 0 || dst == NULL ||
            (scn = d->d_scn) == NULL ||
            (e = scn->s_elf) == NULL) {
                LIBELF_SET_ERROR(ARGUMENT, 0);
                return (NULL);
        }

        ec = e->e_class;
        assert(ec == ELFCLASS32 || ec == ELFCLASS64);

        if (ec == ELFCLASS32)
                sh_type = scn->s_shdr.s_shdr32.sh_type;
        else
                sh_type = scn->s_shdr.s_shdr64.sh_type;

        if (_libelf_xlate_shtype(sh_type) != ELF_T_DYN) {
                LIBELF_SET_ERROR(ARGUMENT, 0);
                return (NULL);
        }

        msz = _libelf_msize(ELF_T_DYN, ec, e->e_version);

        assert(msz > 0);

        if (msz * ndx >= d->d_size) {
                LIBELF_SET_ERROR(ARGUMENT, 0);
                return (NULL);
        }

        if (ec == ELFCLASS32) {
                dyn32 = (Elf32_Dyn *) d->d_buf + ndx;

                dst->d_tag      = dyn32->d_tag;
                dst->d_un.d_val = (Elf64_Xword) dyn32->d_un.d_val;

        } else {

                dyn64 = (Elf64_Dyn *) d->d_buf + ndx;

                *dst = *dyn64;
        }

        return (dst);
}

int
gelf_update_dyn(Elf_Data *d, int ndx, GElf_Dyn *ds)
{
        int ec;
        Elf *e;
        Elf_Scn *scn;
        Elf32_Dyn *dyn32;
        Elf64_Dyn *dyn64;
        size_t msz;
        uint32_t sh_type;

        if (d == NULL || ndx < 0 || ds == NULL ||
            (scn = d->d_scn) == NULL ||
            (e = scn->s_elf) == NULL) {
                LIBELF_SET_ERROR(ARGUMENT, 0);
                return (0);
        }

        ec = e->e_class;
        assert(ec == ELFCLASS32 || ec == ELFCLASS64);

        if (ec == ELFCLASS32)
                sh_type = scn->s_shdr.s_shdr32.sh_type;
        else
                sh_type = scn->s_shdr.s_shdr64.sh_type;

        if (_libelf_xlate_shtype(sh_type) != ELF_T_DYN) {
                LIBELF_SET_ERROR(ARGUMENT, 0);
                return (0);
        }

        msz = _libelf_msize(ELF_T_DYN, ec, e->e_version);
        assert(msz > 0);

        if (msz * ndx >= d->d_size) {
                LIBELF_SET_ERROR(ARGUMENT, 0);
                return (0);
        }

        if (ec == ELFCLASS32) {
                dyn32 = (Elf32_Dyn *) d->d_buf + ndx;

                LIBELF_COPY_S32(dyn32, ds, d_tag);
                LIBELF_COPY_U32(dyn32, ds, d_un.d_val);
        } else {
                dyn64 = (Elf64_Dyn *) d->d_buf + ndx;

                *dyn64 = *ds;
        }

        return (1);
}